1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
ivann1987 [24]
3 years ago
13

X+3y-2z=10, -x-2y+z=-7, 3x+9y-5z=28

Mathematics
2 answers:
NISA [10]3 years ago
6 0
Hmm
what you do is try to eliminate 1 variable in 2 equaions first
we can elminate x's in first and 2nd equation

add first and 2nd equation
x+3y-2z=10
<u>-x-2y+z=-7 +</u>
0x+y-z=3
y-z=3


multiply 2nd equation by 3 and add to last one
-3x-6y+3z=-21
<u>3x+9y-5z=28 +</u>
0x+3y-2z=7

3y-2z=7

we now have
y-z=3
3y-2z=7
multiply first equation by -2 and add to 2nd

-2y+2z=-6
<u>3y-2z=7 +</u>
y+0z=1
y=1

now we can sub back
y-z=3
1-z=3
minus 1
-z=2
times -1
z=-2

sub baack into any equation
x+3(1)-2(-2)=10
x+3+4=10
x+7=10
minus 7
x=3

x=3
y=1
z=-2
(3,1,-2)

Semenov [28]3 years ago
4 0
  
\displaystyle  \\ &#10;~~~~x+3y-2z=10 ~~~~~(E_1)\\  &#10;-x-2y+z=-7 ~~~~~(E_2)\\ &#10;~~3x+9y-5z=28~~~~~(E_3) \\ &#10;\text{- - - - - } \\ &#10;E_1 + E_2 ~~\Longrightarrow~~y - z = 3 \\  \\ &#10;-3 \times E_1  + E3  ~~\Longrightarrow~~ z = -2 \\  \\ &#10;\Longrightarrow\Longrightarrow\Longrightarrow \\  \\ &#10;y-z=3\\&#10;z = \boxed{-2}\\&#10;\text{- - - - - }\\&#10;y-(-2)=3\\&#10;y+2=3\\&#10;y =3-2=\boxed{1}\\&#10;\text{- - - - - }\\&#10;x+3y-2z=10\\&#10;x+3\cdot 1-2\cdot (-2)=10\\&#10;x+3+4=10\\&#10;x+7=10\\&#10;x= 10 - 7 = \boxed{3}



You might be interested in
Why are the mode median and mean call measures of the center?
Contact [7]
Because they are in the center.
6 0
3 years ago
Read 2 more answers
HELLLLPPPP! brainliest!!!<br><br> f = 180° – 50° – =?
Schach [20]

Step-by-step explanation:

f = 180 \degree - 50 \degree = 130 \degree

4 0
2 years ago
Read 2 more answers
There are twice as many Robins has blue jays and their 21 altogether how many blue jays are there
Lunna [17]
R + b = 21
2b = r

now we sub eq 2 into eq 1
r + b = 21
2b + b = 21
3b = 21
b = 21/3
b = 7

2b = r
2(7) = r
14 = r

so there are 7 bluejays (b) and 14 robins (r)...for a total of 21
5 0
2 years ago
Break apart 2 divided by 995
Marta_Voda [28]

Answer:

(995/2) ÷ 2 = 248.75

5 0
3 years ago
Write each complex number in rectangular form. a. 2(cos(135)+i sin(135)) b. 3(cos(120))+i sin(120)) c. 5(cos(5pi/4)+i sin(5pi/4)
bagirrra123 [75]
\bf r\left[ cos\left(  \theta \right)+i\ sin\left( \theta  \right) \right]\quad &#10;\begin{cases}&#10;x=rcos(\theta )\\&#10;y=rsin(\theta )&#10;\end{cases}\implies &#10;\begin{array}{llll}&#10;x&,&y\\&#10;a&&b&#10;\end{array}\implies a+bi\\\\&#10;-------------------------------\\\\&#10;2\left[ cos\left(  135^o\right)+i\ sin\left( 135^o\right) \right]\impliedby r=2\qquad \theta =135^o&#10;\\\\\\&#10;2\left( -\frac{\sqrt{2}}{2} \right)+i\ 2\left( \frac{\sqrt{2}}{2}\right)\implies -\sqrt{2}+\sqrt{2}\ i

\bf -------------------------------\\\\&#10;3\left[ cos\left(  120^o\right)+i\ sin\left( 120^o\right) \right]\impliedby r=3\qquad \theta =120^o&#10;\\\\\\&#10;3\left( -\frac{1}{2} \right)+i\ 3\left( \frac{\sqrt{3}}{2}\right)\implies -\frac{3}{2}+\frac{3\sqrt{3}}{2}\ i

\bf \\\\&#10;-------------------------------\\\\&#10;5\left[ cos\left(  \frac{5\pi }{4}\right)+i\ sin\left( \frac{5\pi }{4}\right) \right]\impliedby r=5\qquad \theta =\frac{5\pi }{4}&#10;\\\\\\&#10;5\left( -\frac{\sqrt{2}}{2} \right)+i\ 5\left( -\frac{\sqrt{2}}{2}\right)\implies -\frac{\sqrt{2}}{2}-\frac{\sqrt{2}}{2}\ i

\bf -------------------------------\\\\&#10;4\left[ cos\left(  \frac{5\pi }{3}\right)+i\ sin\left( \frac{5\pi }{3}\right) \right]\impliedby r=4\qquad \theta =\frac{5\pi }{3}&#10;\\\\\\&#10;4\left( \frac{1}{2} \right)+i\ 4\left( -\frac{\sqrt{3}}{2}\right)\implies \frac{1}{2}-\frac{\sqrt{3}}{2}\ i
3 0
3 years ago
Other questions:
  • Square root 2 is between 1.4 and 1.5
    11·1 answer
  • Pls help fast this is khan academy
    14·2 answers
  • a mover uses a ramp to pull a 1000 n cart upto the floor .8 meters high. If it takes a force of 200 newtons to pull the cart, wh
    15·1 answer
  • Find the multiples of 9 that are less than 100
    10·2 answers
  • Complete the equation of the line whose slope is − 2 and y-intercept is ( 0 ,-8)
    15·1 answer
  • Carly bought 3 pounds of birdseed.how many ounces of birdseed did she buy
    5·2 answers
  • In a survey of 2100 people who owned a certain type of​ car,735 said they would buy that type of car again. What percent of the
    15·1 answer
  • What number is 14% of 110?
    12·2 answers
  • What is the answer for this equation 3x-2=2x+9
    14·1 answer
  • I want to know the answer of these questions and the questions are
    15·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!